If the street lights are running on coal-fired electricity - how much carbon dioxide emissions are prevented by switching to LEDs? In the case of a number of small communities in Arkansas -- 1,329 LED traffic signals and 706 LED arrow signals to be installed in 40 to 45 communities that have one to five traffic signals. For the net life cycle of LED lights, air pollution is reduced by 41 million pounds of carbon dioxide, which is the equivalent of removing 3,599 cars from the road per year